# definite integral

• Dec 1st 2008, 11:03 AM
sss
definite integral
• Dec 1st 2008, 12:57 PM
Jason Bourne
$\int_{\frac{\pi}{6}}^{\frac{\pi}{2}} \frac{cosx}{sin^7x}dx = \int_{sin(\frac{\pi}{6})}^{1} \frac{1}{u^7}du$

by using the substitution u = sin(x)
• Dec 1st 2008, 01:04 PM
Jason Bourne
Quote:

Originally Posted by sss

$\int_1^{e^8} \frac{dx}{x\sqrt{lnx}} = \int_0^{8} \frac{du}{\sqrt{u}}$

using the substitution $u =ln(x)$

I think you could do the other integral by parts